1. Field of the Invention
The present invention relates to solenoid actuated valve devices and more particularly to solenoid actuated valve devices for controlling the flow of fluid in proportion to the electric current supplied to the solenoid.
2. Prior Art
A conventional solenoid actuated valve device comprises a linear motor of the movable coil type and a valve means. The linear motor includes a core, a bobbin slidably mounted on the core, a solenoid coil wound on the bobbin, permanent magnets with the magnetic flux of each intersecting the windings of the solenoid coil at right angles and a yoke or body forming a magnetic circuit with the core. The valve means in general include a sliding valve member which slides with the bobbin on the core in response to the electric current flowing through the solenoid coil to thereby proportionally control openings formed in the core between an inlet port and an outlet port. The sliding valve member is always biased by means of a pair of springs in a direction so that the sliding valve will close the openings to thereby interrupt the fluid communication between the inlet and outlet ports.
In such prior solenoid actuated valves, one end of each of the springs is connected to the solenoid coil and the other end of each spring to a terminal which is electrically connected to a suitable power supply. Thus, the springs are adapted to function as conductive members. Since the said other ends of the springs have to be connected to terminals, the said other ends of the springs are securely supported in the body of the solenoid actuated valve devices thereby making it impossible to adjust the biasing forces of the springs which bias the sliding valve with the bobbin. Thus, the timing by which the sliding valve controls the openings cannot be adjusted and the desired flow of fluid cannot be properly controlled.
Additionally, in such prior devices, the said one ends of the springs are connected to opposite ends of the solenoid coil through the bobbin. Since the bobbin is normally made of metal, the connecting portions thereof between the springs and the coil are apt to short-circuit the coil so that electric current cannot flow through the coil thereby preventing the operation of the valve.